


Splice

by Miss_Lv



Series: Monster Destiel AUs [3]
Category: Supernatural
Genre: Bottom Dean, Bullshit Science, Codependency, Creature Castiel, Dark Dean Winchester, Dubious Morality, Horror-ish, I Know Nothing About Science, Implied Mpreg, Interspecies Sex, M/M, Mad Science, Obsessive Behavior, Pseudo-Incest, Science Experiments, Scientist Dean, Splice AU, Top Castiel
Language: English
Status: Completed
Published: 2015-10-05
Updated: 2015-10-05
Packaged: 2018-04-24 21:16:16
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 15,546
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4935646
Author URL: https://archiveofourown.org/users/Miss_Lv/pseuds/Miss_Lv
Summary: <blockquote class="userstuff">
              <p>Spn Kink Fill: Horror movie Splice AU with Dean as the scientist who creates the creature hybrid Castiel.</p>
            </blockquote>





	Splice

**Author's Note:**

> Pounded this out in a day, I've read it over a few times to comb out errors but if you notice any please let me know!

Dean knows better.

But scientific progress, real leaps and bounds, were usually controversial. People often scorned any sort of unethical developments while still taking all of the benefits that came with them.

Dean personally thought it was badass in a way; sometimes you had to take a risk to get the big pay out.

So when the Hunter Labs board rejected the proposal Dean didn't give up on the idea.

The thing was, they had already done it successfully.

After years or research and careful exploration, they had successfully spliced organisms. Two little wiggling creatures the size of Dean's hand. They were made up of hundreds of various characteristics from various small mammals. The genetics research corporation Hunter Labs had patted them on the back. Dean and Sam had been given a big bonus and then spent the next three years watching their creations develop. Bones and Ruby were both healthy living specimens that showed accelerated growth and minimal decaying. Sam was currently in the process of balancing that, trying to keep their bodies growing without anything vital giving out. They had planned a five-year live span for them and everything was still on track.

In two years they would die and be dissected thoroughly. But any big developments from the pair were done. Dean had tried to make them viable for breeding but it hadn't worked, Bones had been sterile and attempts to artificially impregnate Ruby had failed.

So Dean had put a proposal together to get permission to create another pair, to use larger breed mammal splices this time. While Dean hadn't been reckless enough to suggest a human aspect, he had left the possibility out there.

The end goal had always been to do it.

To create human splices in order to take medical research to the next level. If they could grow organs, if they could develop self-healing organs, it would change the world. If animal splicing could be merged with humans they could learn how to regrow lost limbs or have injections that would destroy cancer and repair damage. It could change everything.

But Hunter Labs had taken one look at the research and rejected it.

"It's not surprising Dean," Sam consoled afterward, the two of them in the lab watching Bones and Ruby wiggle around their enclosure. Sam was half focused on some data coming up his laptop as he talked while Dean was slumped back in his chair, frowning at his desk.

"Ruby and Bones are the first of their kind. It's gonna be years of researching them before we can ever duplicate them, much less a higher life form. It's delicate work when it comes to the ethics of it."

"God Sammy, it's gonna be decades before anything happens at your rate," Dean grumbled and Sam shrugged.

"I think this is something Dean, we created a life form, something new via currently existing specimens. The science world is still reeling from it."

Dean frowned harder at his desk. Sam was the one attending the conventions and talks, Dean had loved the spotlight at first but when he grew dissatisfied with their work he pulled away. Flipping his laptop open he pulled up the latest data stream and frowned at the layout. It was near perfect but still missing a few aspects, there were imperfections that needed to be ironed out.

"What is that," Sam asked with growing incredulity as he peered over Dean's shoulder, his paperwork slipping to the floor unnoticed as he jumped up to read the data. "Dean," there was an underline of disapproval and dread in his baby brother's tone and Dean rolled his eyes. A small part of him had hoped Sam would understand, but he wasn't surprised. Sammy loved his rules.

"Relax, it's just a theory. It probably won't happen in our lifetime."

Dean didn't miss the way his brother's shoulders slumped with relief.

"Huh," Leaning in closer his brother read through the data sequence with more care and less outraged horror. "This is actually well planned, you really thought this out."

Dean snorted but rolled his chair away so Sam could step closer and read through it, his brother already locked on and making edits. They had always worked together on their projects, Dean developed and Sam perfected.

"It was just a boredom experiment at first, for when I needed a break from paperwork. A game."

Sam nodded his head, not really listening and Dean huffed a smile.

Typical nerd.

Standing up he left Sam to it and went to check up on Bones and Ruby. Their readings came back clean though, nothing was worrying. Ruby wiggled passed and Dean watched her, leaning against the glass.

They were ugly little things.

Promotion images usually focused on their DNA strands or something scientific rather than actual pictures of them because they were essentially fat worm rats. Next time they'd try to add fur and made them more 'cute'. This round they had just worried about it actually working more than looks.

Sam kept typing away and Dean glanced at him through the glass to the other side where their desks were. Nothing on his face him gave away, his triumph of having Sam finishing the data sequence.

 

Dean left it alone for a long while. He moped around more and slept with a cute little thing in finance, he played the role his brother expected and waited.

A month later Sam was off on a week long run to various conferences to present the aging data and Dean was left alone with the lab.

The thing was making sure none of the cameras picked it up. Hunter Labs wasn't some tiny place and its security was top notch. Thankfully Dean's best friend was a computer hacker. Charlie waved her magic fingers and on the Monday Dean spent his day working diligently. Tuesday the lab cameras played a mix of Mondays footage and Dean went to work.

Ruby and Bones had needed four months to completely develop. But as the first experiments they had been cautious with them, giving them way more time than they really needed. Four days was cramming a lot in, but Dean didn't plan a full development in the chamber. Dean fondly called it Old Betsy but it was essentially a Frankenstein of an artificial womb, monitoring chamber, test tube and a few other things Dean had thrown in. While he knew his way around research and development this was Dean's thing. Give him anything, be it machine or creature and he would find a way to make it work. He was making radios out of spare parts at five and by ten advanced machinery from house appliances. So it didn't take much to speed Old Betsy up some and fast-forward the incubation.

 

Dean and Sam shared an apartment in the city. It was a nice place they moved into after their big bonus with Bones and Ruby's successful development. But it was a two-bedroom place with nowhere to hide anything. Dean had spare parts all over his room and with some ingenuity and a few friends in auto shops and science equipment labs; he rigged up a smaller version of Old Betsy. Dean named it Betsy Two and shoved it in his closet. Carefully he drilled holes to run power cables under his bed and then shoved a dresser to one wall to hide them. Excitement made him jittery but Dean focused in and got everything set up.

He went to work early the next day and checked in on Bones and Ruby before pulling up the monitor set up in his laptop. The reading on the new specimen looked good and Dean grinned into his hand.

Getting it out of the labs was no easy thing.

People stole high-end equipment and company sabotage and betrayal was a real thing in the science world.

Shit got crazy.

Dean could still remember some guy with sample vials shoved in his briefs.

So security was intense and serious. Charlie could make the computers and tech do what Dean wanted but the body scanners built into the doors would give him trouble.

So Dean defaulted to what he knew best, charm and sex.

The day the initial incubation was done he took out the new specimen. It was creepy as fuck in that it was humanoid. Little chubby human limbs and a head with two eyes, a nose, and mouth. The spacing was fucked up though, the neck too long and limbs out of proportion. The fingers hooked with talons and the leg joints were digitigrade. Its eyelids were too big, no doubt it's eyeballs would be huge. But it remained asleep, little limbs twitching once and again. It was small, Dean used the same cylinders they used for Ruby and Bones so it would be easy to move.

Dean had everything timed carefully. Betsy Two at home was set up and ready to go and the tube encasing the specimen would self-support for two hours. Very gently Dean loaded him into a backpack and shut down the lab.

The security guard was a nice guy that had worked there for years. Dean knew him vaguely and had hooked up with him a few times over the years. So when he started his shift Dean went for it.

The doors through security could be manually turned off and on for moving equipment. So Dean dropped by, grinned brightly and dropped to his knees to blow the guy. The man was too startled to say a thing but he went with it. Afterward, Dean slipped out the security door with the scanner ‘accidently’ turned off during their fumbling.

Betsy Two ran smoothly and it took the specimen tube with ease. Dean loaded the data to his phone so he could monitor it remotely and spent the weekend watching it avidly.

 

"You're pleased with yourself," Sam frowned a few days into the next week. He peered suspiciously at Dean who grinned back in return.

"Spent all week getting laid. Even sucked off a security guard," Dean waggled his brows and watched his brother curl his lip.

"Dude, I don't want to know."

"Good week Sammy. Good week."

"Whatever. Can you check the calibrations for the equipment, everything is coming up off on the report."

"Yeah, I recalibrated everything. It was doing that last week. Couldn't figure out what machine specifically was doing it so I figured we could just reset everything. I logged everything we used in the last months." Dean pushed up from his desk to peer at his little brother's computer. "I can realign whatever needs to be."

 

Dean went to bed early and turned off his bedroom light before opening his closet and peering at the specimen. "Hey buddy," he whispered, kneeling down to examine it. Dean knew it was growing and he tried to see any physical differences.

"You're going to be amazing."

 

"New sex pal or something?" Sam asked when Dean checked his phone absently and Dean grinned at him with a leer.

"A couple Sammy, they wanna do all the things," he teased and his brother gave him a disgusted embarrassed look before turning back to his computer. Dean checked the readings on Betsy Two one last time before starting to compile the latest data on Ruby for the next submission.

 

Dean made a habit of sitting by the tube and talking at the specimen. It got all twitchy when he did so and Dean was certain it was developed enough to hear him. Dean had tried to splice imprinting onto it but it was tricky to figure out still. Isolating something that wasn't a physical trait was hard as hell and they still hadn't figured it out exactly. Which was probably why the specimen had developed secondary arms. Two little wiggly joints that started from its spine and ran along its shoulder blades. The limbs bent inward and were flat against it's back.

They looked disturbingly like chicken wings.

"Ruining good food for me," Dean grumbled at the tube. He'd ordered them last week but the sight of them turned his stomach.

"Little feather brain."

Sam being Sam caught on to something but Dean dodged him with all the skill of a brother used to a nosy little sibling. He played it off as a game at first and then he played the distraction card, an ace up his sleeve he'd been working on.

"He never shuts up about you, always going on how you've got the brains and the beauty," Dean griped as he took in the data on the screen. Jessica, the behavior analyst for Ruby and Bones was blushing red as she tried to focus on the little guys in the cage. "If I have to hear one more sigh about your smile I may have to kill him," Dean added for good measure.

Sam walked into the lab at that exact moment and blinked when Jessica flashed him a bright smile and asked how his week had been.

Normally Dean avoided Sam in love because he always got distracted. Shit got messed up and paperwork starting showing up late. Sam was the kinda guy who fell head over heels. The good side to it was that he completely forgot Dean existed and started sleeping over at Jessica's place. Dean had to pick up some slack on the projects with Ruby and Bones but it was worth it to watch his own private project develop without any nosy brothers looming.

 

The specimen was ready before the due date.

Dean was watching Bones follow Ruby around the enclosure bored and in the next second his phone was vibrating crazily. The data monitoring for the house project was going crazy, vials over the safe level and the tube showing power failure.

"Fuck!"

"Dean," Sam blinked up at him as Dean jumped up and grabbed his coat. "Girlfriend emergency. I've gotta go!" He rushed, running for the door.

"What? Dean, we're in the middle of an experiment! Dean!"

"Sorry!" Sam was going to be pissed but Dean didn't have time. He watched the vitals of the specimen jump all over the place as he drove like a demon to get home. When he pulled into the packing lot the vitals went silent. The terminated signal flashing to indicate it had died. Dean swore out loud, running a hand through his hair as he leaned back into the car seat. He had been so close, only two weeks away from extraction.

Parking the car with more care Dean decided to call it a day rather than head back to work. He locked up the car and walked up to the apartment. Heading to his room he frowned at the liquid under the closet door and slid the door open.

The tube was shattered on the floor.

Empty.

Dean's first thought was that someone stole his specimen but his window was still closed and the door had been locked. A tiny shuffle made him freeze and Dean peered into the closet. A tiny wet lump was visible under a pile of dirty laundry. Dean crawled into the closet, not caring as he got tube goo all over his hands and knees, a sharp piece of glass nicking his palm as he wedged himself in.

"Hello, hi there," he coaxed gently with a feeling of awe. Carefully, he peeled a t-shirt back until bright blue eyes peered at him. They were huge and Dean could admit they were adorable. Hunter Labs had wanted a cute specimen after all.

"Hi, hello," he mumbled, reaching out very carefully to touch the specimen. He watched it try to focus its eyes on his fingertip and its nostrils flared as it scented. The little guy was bumbling, but he still move quickly, latching onto Dean's finger and sucking noisily.

Nursing instinct. It had nursing instinct.

Dean grinned as he gently picked up the laundry pile with the specimen, letting it suck at his finger as he brought him close to his chest.

"Hi," he whispered.

Dean had formula started, a mix of human and animal based on the splices he used. It was under his bed and half finished so Dean dragged it out and slapped it together quickly. The specimen flopped around in its laundry nest and eventually made weak sounds, as it got used to vocalization the cried became more urgent and Dean rushed to get the mix into a liquid format. He left the specimen on the kitchen table in the laundry pile and rushed to mix the formula up on the stove.

"Alright! I'm going," he told the little whiner as he grabbed a freezer bag in place of a bottle. Tying it with an elastic band, Dean just remembered last second to check the temperature and then had to wait while it cooled off. The little guy sucked at Dean's finger as it waited, watching him with wide eyes. All six limbs were twitching and showing mobility.

Dean eased his finger out of its mouth and put the tip of the bag in. The milk overflowed and the little thing choked once before swallowing and then greedily drinking it all down. Dean watched with a wide grin, staring down at the brand new creature he had made. Way beyond little low-level intellect worm rats, a living breathing life that was going to really change the world. The specimen blinked up at him, eyes locking on Dean's gaze and watching him as he gulped down the formula. It finished the bag and before Dean could do anything the little guy promptly puked all over itself.

 

Taking care of the specimen was nothing like looking after Ruby and Bones. It wasn’t an infant in a human sense either. He just sort of sat there in the nest Dean made from laundry and watched Dean. He was laid out on his back and helpless but fine with it. It was almost frightening how human he looked, but more so how obvious it was that he wasn't a human.

He wasn’t crying or whimpering now, just sitting there watching Dean watch him.

“So hi,” Dean started nervously, reaching out to touch a chubby arm. The specimen squirmed but seemed please, it’s own bumbling fingers reaching for Dean. Letting him grab at him, Dean took the opportunity to inspect him closer. His skin was soft like a human on his face, neck, stomach, and inner thighs but beyond that it was tougher with a grit to it, like sandpaper almost. The secondary limbs coming from his shoulders were functional in that he could move them but they lacked hands, long joints with plenty of muscle and a growth of downy soft hair covering them. He had similar on his head, darker with fine hairs coming in, a few inches long that ran down his back and stopped just above his hips.

When Dean examined his foot and the specimen shocked him by giggling.

Dean felt his stomach drop out as the enormity of what he had done suddenly hung over him.

Swallowing nervously he kept up his inspection.

“Well need to name you, Ruby and Bones were Sam’s idea and I didn’t really care but Sam’s not here to name you,” he babbled weakly. Grabbing his personal laptop, he opened a file and started documenting everything he could. He pulled out his phone to snap pictures. Dean tried to pull back and be more formal, scientific.

But he couldn’t deny that it was kid in front of him. A messed up, genetically altered baby boy.

“When I was a kid,” Dean started, looking at the file as he filled out everything he could without equipment. “There was this girl, Cassie. I was right in love with her, thought we’d get married and have kids, the whole picket fence thing. Anyway, we decided to follow our parents tradition of naming. I’m named after my grandma Deanna and Cassie was named after her grandfather Castiel.”

Dean moved them to the bedroom, yanking a bathroom scale from under his bed and putting the specimen into a towel, carefully weighing him. The boy lay compliant, wiggling to look around but letting Dean do as he pleased.

“So I’m thinking Castiel. You’re as close as I’ll ever get to have kids so why not?”

Castiel was blessedly quiet and when Sam got home Dean hid the specimen in the closet again. He’d set up a bed for him, using his extra blanket and a pillow to make something nice. He tucked the almost boy in and thanked his luck when Castiel immediately dozed off.

“What the hell Dean!” Was Sam’s greeting and Dean shrugged weakly as he closed his bedroom door and walked into the kitchen. It was still a mess after the panicked formula making so he started to tidy up, dumping things in the sink and wiping counters while Sam watched him incredulously.

“You yell something about a girl and take off mid-experiment and then don’t answer your phone and you’ve got nothing to say?”

Dean had carefully considered his options and finally decided he needed something heavy and hard to get out of this. “My ex called, Lisa. Told me she was about to kill herself.”

When Dean lied he talked too much, rambled on. He knew that though and so now he remained quiet as he cleaned and let Sam put his own story together.

“Jesus,” Sam breathed, sitting down hard at the table.

“Yeah. So I went to see her, talked her down and got her to go to the hospital. Ben’s with family I guess. Sorry to take off like that but I freaked out.”

“Yeah, no, it’s ok Dean. Jesus, you should have said something.”

“Sorry Sammy, I meant to call but everything was too intense.” Dean focused on the cupboard while he lied to his brother. But Dean knew Sam and without more data on the new specimen his brother would freak. Dean just needed time to get some world changing info on Castiel and then he’d tell him.

“I was going to hang out with Jess tonight but-“

“Go man. I don’t mind. I’d like some time alone really.” Dean winced at that because when did he ever want alone time? “I was thinking of calling a friend over for some distraction,” he added quickly.

Sam nodded his head, still looking at Dean like he was a wilting flower.

“Go,” Dean shooed and Sam got up and lumbered over to give Dean a tight hug.

“S’all right Dean.”

“I know Sammy.”

 

Guilt was never fun but Dean swallowed it down as he went back to the bedroom once he was sure Sam was gone for the night. Castiel blinked up at him when Dean checked on him, the specimen had pulled his clean shirts hanging down to make a nest and was curled up under a button up. Dean leaned on the wall and just watched him.

“It’s gonna be worth it in the end. Sammy wouldn’t understand.”

Blue eyes peered back at him, watching Dean watch him.

 

Dean woke with a jerk. He’d passed out on the bed, his laptop still open beside him. Sill dressed he sat up and yawned. It was seven am and another jarring noise came from the kitchen. Dean noticed the closet opened a crack and jolted up to check it. It was empty.

“Fuck,” Dean breathed as he dashed into the kitchen.

Castiel was on the kitchen floor covered in the formula powder and dragging pots.

He had also doubled in size.

"Holy fuck," Dean whispered.

The little guy sat obediently for Dean on the kitchen counter, watching the formula in the pot mix while Dean cleaned him up. He reached out towards the stove once but Dean stopped his hand. Clawed fingers curled around his own palm, even a light pressure was enough to bite. Reaching out he poked his finger in the specimen’s mouth and it latched on at once, suckling away and Dean could feel sharp teeth nipping.

A predator.

Ruby and Bones had been specifically made into prey animals. Dean tried to ensure Castiel would be the same but the presence of the claws and teeth suggested otherwise. Built to kill.

"It's been a day, barely twenty-four hours." When Dean made the specimen, he had tried to instill accelerated growth but this was far beyond anything he thought capable. The secondary arms on it's back were pulled up tight but growing a thick fuzz, his legs had three joints over a human’s two and his toes were long with the dexterity to grip. A thin tail swished on the counter and those wide blue eyes peered at Dean.

"You're amazing!" He told Castiel with a grin, the boy blinking owlishly before making his own little smile.

"Look at you, monkey see, monkey do, huh?" Dean looked at the mess on the floor and realized that Castiel had been trying to make himself formula. Dean gave him half straight out of the baggy system but the other he shoved into Sam's blender and dumped some oats in. Blending it until it was a porridge he put the mix in a bag and snipped the corner off. Castiel took it and Dean could see his face working out the strange consistency but he still slurped it down.

"We'll need baby food if you've already got teeth coming in."

After eating Castiel didn't doze off this time. Rather he wondered the house, wobbling around on his feet and hands with the occasional two leg walking. Dean followed him with his phone camera. It was clear that Castiel had imprinted on Dean, when he was startled by traffic outside he rushed to Dean's legs, curling up and clinging to him.

"It's alright, nothings gonna get you buddy," Dean soothed.

Taking blood was hard.

Castiel whimpered when he was jabbed and he wiggled around as Dean tried to get the sample.

"Hey, come on, stop it. Be good," Dean had to pull the needle out though, to keep Casitel from hurting himself. The boy sniffled and whined, not crying but clearly distraught. Dean wondered if he could even produce tears.

Staring into the kitchen, Dean frowned at the pots as an idea slowly formed in his head. Castiel had been covered in formula powder and had pots this morning. He'd been trying to make himself food as he'd seen Dean do. Mimicking was a key teaching tool for animals.

"Watch me," Dean explained as he rolled up his shirt and showed Castiel. Dean easily took a sample of his own blood and when he tried Castiel whined but let him.

"Good boy," Dean praised, rubbing Castiel's hair in reward. He squirmed in pleasure and peered at his Band-Aid, pressing it side by side to Dean's arm and his own Band-Aid.

"We match," Dean reassured him. Castiel made a soft cooing sound, rubbing the smooth fabric of the Band-Aid curiously as Dean gave him a full physical, careful to measure his height and weight precisely. Dean wished he had the lab's equipment to better document everything but he would have to make due.

After consideration Dean spend the rest of the day playing hiding games, showing Castiel to duck low and tuck up into places and to be unseen. Dean would walk out of a room with Castiel standing in the middle of it and then return back into an empty space and hidden hybrid. They played with shorter hiding times until Dean could turn in a slow circle and Castiel was gone.

He'd done it in jest but when he couldn't find him anywhere obvious Dean was struck with how eerie it was.

"Castiel," he called and a soft thump under the couch gave him away before the little guy came over to Dean. Butting his head to Dean's chest Castiel crawled right into his lap and clung happily. Dean let himself smile as he rubbed the hybrid's back a bit. Castiel was a bit strange, but he wasn't dangerous or anything. Lots of prey animals were amazing at hiding as well.

Castiel stayed in the bedroom when Sam got back.

Dean cooked a simple dinner and avoided his brother's sad eyes. He turned in early and hid in his room. Curled up in bed in case Sam checked on him, he typed up new theories for Castiel and outlined experiments to try and samples he would need to take. At first Castiel was content in his closet nest but an hour in he was peeking out, big blue eyes peering at Dean while he worked. Not long after Castiel was under the bed and eventually trying to scurry over the edge. For two days old he was surprisingly mobile.

"Dude, you can't be out here," Dean hissed, glancing at the closed bedroom door wearily. Castiel made a low unhappy sound but kept trying to get up. Dean already fed him again and he had blended bananas and strawberries in a cup, but Castiel wasn't making his food sound. With a huff, the little guy finally pulled himself up over the edge of the bed and sat proudly at the foot, looking back down over the height he had just climbed. His excited eyes turned to share it with Dean and he felt his heart melt a touch.

"Come here then," he coaxed and lifted the blanket. Castiel scuttled over and with Dean guiding him he curled up under the blankets at Dean's side, mostly hidden by pillows.

"Quiet," Dean told him, he'd used the word all day to signify silence and Castiel seemed to grasp it. He snuggled into Dean's side and dozed off.

Come morning Castiel had grown again. His spurts happened at night. While he had gained an inch during the day, at night he added a foot and a half. Dean theorized that it was easy on his body to be unconscious when the growth happened; the muscles and bones had to be aching as they expanded so rapidly. Castiel was a suck in the morning too, curled up and making soft sad whines. Dean thanked everyone above and below when Sam was still sleeping. He snuck into the kitchen and made the formula again, this time he added oatmeal, bananas, and honey before blending it all but leaving bits to start chewing. Castiel didn't lift his head or move an inch as he latched on to the bag and drank. Dean slid back into the bed with him and rubbed his hair soothingly.

"Poor guy, It’ll get better."

Castiel grumbled softly and drank quietly.

Dean played on Sam's sympathies for the day but it backfired when he and Jess showed up in the evening, the security guard Dean had blown in tow.

"You remember Michael right?" Jess asked with a wide smile, clearly friends with the guy.

Sam stood over her with big eyes, silently signaling that if Dean wanted he'd find a reason to get rid of the guy. But Dean had said he wanted to hook up and if he over played this Sam would start hovering none stop. So he smirked at the guy and played the host.

His bedroom door was closed and Dean tried not to look at it too often.

They ordered out and drank beer chatting in the living room. Dean was acutely aware of every squeak from his room, but he did his best no to react. Sam noticed but seemed to think it was something other then the creature Dean had made in spite of every moral and ethic law against it.

As the evening wound down Sam and Jess left for her place for the night and Dean went for it. If he kicked the guy out Jess would find out and thus Sam, Dean had pretended to like him all evening and he did actually feel bad about using him.

"Look, I'm not a dating guy but I'm down for sex?" Dean announced bluntly and the guy looked relieved.

"Thank God, Jess means well but a fuck doesn't mean marriage is around the corner," Michael replied and Dean grinned.

To avoid the bedroom, Dean let the guy screw him on the couch. Leg spread he panted and actually really enjoyed it. The guy fucked him good, kept a rough touch that Dean had always liked. Dean swore and arched his back off the couch as he came, jerking himself off while Michael pounded into him and got off as well.

In the aftermath of it Michael turned and frowned at the hallway and Dean froze up.

"What is it?"

"You have a cat or something?"

Damn it Castiel.

"Nah, but the neighbor does and it get in through the window sometimes, light bottom and dark head and back?"

"Yeah, I think so."

Dean shrugged and promised to find it and shoo it off. They cleaned up and Dean showed him out, Michael didn't seem upset not to get an overnight invite but they exchanged numbers and Dean promised to call for another hook up sometime. Once the door was closed he leaned against it and sighed.

Secret home experiments where stressful as hell.

Dean jerked when something touched his foot but relaxed when it was just Castiel, peering up at him. His little nose was snuffling and he sniffed awkwardly at Dean's crotch.

"Sorry about that, could use a shower I imagine," he grumbled.

Castiel followed him and spent half the shower terrified of water and the other half loving it, slip sliding at Dean's feet and nearly killing him multiple times. Afterwards when Dean relived himself Castiel watched and then mimicked him. He loomed over the toilet and missed half the time but he had his first piss and bowel movement. Dean cleaned up the aftermath and hopped in for another shower to feel clean again.

 

Sunday morning Castiel was to Dean's waist. He was filling out and feathers were staring to come in along his extra shoulder limbs. Wings, Dean realized, like an angel. Of course with their placement and size Castiel would never be able to actually fly but they were cool to look at.

The thing was, though, it was becoming clear that Castiel couldn't stay. At the rate, he was going Dean would never be able to hide him. He was getting way too big and hiding in the closet wasn't going to work. Just in the bedroom Castiel was pacing around, bursting with energy that a run around the apartment wasn't going to solve. They needed more room.

Dean fed Castiel and got him to nap despite his energy. Once he was dozing Dean ran all his supplies to the car and packed himself a bag. Everything they could possibly need he shoved into to the impala. It was mid morning so people were walking around the building and parking lot. Dean wiggled Castiel into a shirt and tied a bathrobe belt around the middle. He threw on a hoodie over it and Castiel looked like a kid that dressed himself. Messed up but passable. Dean put a baseball cap over his head and prayed to the science gods for luck. One old lady did a double take, but otherwise they made it to the car, Dean carrying Castiel and clutching him tightly to his chest. Castiel was delighted with his clothing and the new sights, peering out the window as Dean pulled from the lot and hit the freeway immediately. He avoided driving side by side with anyone and got out of the city.

A few hours out he started to relax when no cops and swat teams showed up. He turned on the radio and Castiel crooned at the speakers as the music played.

"Like that?" Dean asked and Castiel made a happy sound, rubbing his face to the speaker and listening to Bon Jovi wail about love.

The farmhouse was empty as Dean expected.

Bobby would check in on it and Dean would crash there a few weeks out of the year so it was in good repair. They arrived at nightfall and the darkness made it easier to pack everything without worrying someone would see Castiel. That and there was no one around for miles. Literally.

So Dean let Castiel play in the mud while he moved boxes, the hybrid was all over the place, sniffing, touching and even licking things. He never left Dean's sight though, when Dean went into the house Castiel trailed after him. When Dean went to the car for another load Castiel followed and watched.

 

Calling Sam was awkward.

"Are you sure you don't want me to come with you?"

"Nah Sammy, I'm gonna visit with Ben and hang out for a bit. I'll be fine. I called work and got the week off on emergency leave."

"You're lucky they let you," Sam sighed but it was the slowly accepting it sigh so Dean grinned.

"Sounded like someone had mentioned something was going on already," Dean guessed and his brother's guilty silence was enough to confirm it.

"I'll be fine, text me if you're worried. I'm just gonna take some time and relax." Lisa had moved after the break up so Dean had the perfect excuse now, pretending to be a state away.

"Alright, I'll see you in a bit alright?"

"Yeah."

Dean hung the phone up with a huff. Castiel peered up at him from where he was sprawled on the couch. Dean was sitting on it with Castiel spread out on his belly, chin on Dean's thigh.

"Sammy over reacts. He always has to follow the rules ya know? When we were kids he was all for fun and adventure but now he's strictly by the book. Can't really move forward with all those dumb rules can we?"

Castiel crooned and Dean grinned at him, reaching out to rub his hair and massage his scalp. The hybrid melted into the couch with a happy sigh.

With time and patience Dean coaxed Castiel into letting him take blood and samples regularly. They got into a routine where Dean would sit Castiel in front of the TV while he collected samples. Castiel was endlessly fascinated with watching shows and Dean left it on children programing most of the day if Castiel was good about letting Dean take samples of blood and bits of skin and hair. Saliva and claw clippings, anything he could think of testing.

Charlie, true bro that she was, helped Dean out by rerouting some equipment that let him really set up shop. Combined with what he brought himself and what was stored at the house, Dean had a decent little lab going.

During the day they worked, Castiel watched TV really, and Dean worked on the samples and recorded everything. He had enough basic materials to mix up a balancing formula for the age acceleration and gave Castiel an injection. It slowed it down a touch but Castiel was still aching and sore in the morning after a sleep cycle. Dean mixed him some painkillers and started dosing him in the mornings. It left Castiel sleepy and clingy, following Dean with one hand on his shirt. Dean could lead him into a fire pit and the half awake hybrid would probably never notice.

But for his clinging, Castiel kept out of the way. He was curious about everything but never touched anything Dean didn't hand him. It made it easy to have a lab set up in the dinning room with no worries Castiel would touch anything harmful.

After watching TV and Dean for a few days, Castiel began to wear pants. With his secondary limbs/wings coming in he couldn’t get a shirt on but pants he would shove into. The first time he wore a pair of Dean’s he kept a hand constantly on them to hold them up and tripped every other step. Dean smirked and watched for a bit before cutting the jeans at the knees and getting a belt. It looked ridiculous but Castiel was clearly very pleased and proud. Come morning he would wake up and follow Dean, mimicking his morning routine of waking up which was essentially Dean getting out of bed, pissing, brushing his teeth, and getting dressed. Anything Dean did Castiel wanted to copy. It was normal behavior for young mammals and pretty cute so Dean worked with him, letting Castiel hold harmless vials and hand him the eggs while Dean cooked. Little things that made the hybrid happy.

In the evenings when it got dark Dean would walk through the field with Castiel following. While Dean walked a lazy straight line Castiel was all over, trotting or outright running through the tall grass. His clumsy movements melted into something smooth and swift with time. Dean tried to record him but couldn't get good quality. It was a shame as watching the hybrid weave through the grass, swift and precise, was something else to see. Eventually Dean hoped to set something up to record and test his speed.

Throughout the week Dean started Castiel on baby food and quickly moved into solids. He mixed health powders with veggies and fruit to try and balance Castiel out, as well as meats and grains. It was by the book for a healthy human.

But Castiel was a hybrid with instincts instilled. Even without Dean teaching him it, Castiel took after a rabbit and brought it back to Dean. It was still alive but badly mangled. Pitying the animal Dean took it from Castiel who gave it up freely, looking for approval.

Castiel stood at his side and was Dean's height now. His wings had come in, long black glossy feathers that Dean had to Google how to clean. True to his prediction, Castiel couldn't actually use them. They were the length of his arms and far too small to bare his weight. But they fluttered at his back, useful as limbs for Castiel to lean back on or gain leverage with. Dean liked them; they were soft and gave Castiel a less intimidating look.

But he was still a wild animal in many senses; the rabbit was a reminder of that.

"Wrong," Dean whispered harshly and knelt down, motioning for Castiel to follow. The hybrid drooped at Dean's tone and obeyed instantly, rushing to correct his mistake.

"Watch me," he commanded and with a quick jerk he snapped the rabbit's neck.

"See? We don't make things suffer." Castiel watched it all, his keen eyes taking it in.

Dean took them home and had Castiel watch as he skinned and butchered the rabbit. John had hunted and Dean could remember learning from him, the proper way to prepare an animal.

"Maybe we'll see if there are any deer around, would feed you and save me some money," he mused. And Castiel rested his chin on Dean's shoulder as he stood behind him, watching Dean cook up the rabbit meat.

"You'll learn," Dean told him when Castiel sighed, clearly morose to have been scolded by Dean. "We'll figure it out together," Dean promised and reached to rub Castiel's hair affectionately. The hybrid pushed closer and snuggled into Dean's back affectionately. Rubbing between his eyes, Dean traced the length of his brow and peered at Castiel's too wide apart eyes. It had stopped looking so unnatural to Dean of late and it was hard to imagine Castiel any other way.

"Go watch TV now," Dean shooed and Castiel went obediently.

 

Sometime in the night, a crash woke Dean. He jolted up before slumping back into the bed. Yawning he sat up to yell at Castiel but froze when he found the hybrid perched on the bed, head cocked to the side as he listened. They could both hear someone downstairs.

Getting out of bed, Dean swore as he dug into the closet for a rifle. It wasn’t common but robbing farmhouses was a thing. They were isolated and the Winchester house was known for being empty most of the time. Dean hoped it was some dumb kid who would run for it and not someone desperate enough to try and fight. Break-ins in rural areas usually went one of those two ways; either someone running through the fields or someone dead.

Loading up the gun quietly, he headed downstairs but stopped at the first step to turn and silently motion Castiel back into the room. The hybrid had been following him and he paced and hesitated before finally going, watching Dean with wide and worried eyes.

Dean knew every creak of his childhood home so he slinked around in the dark soundlessly, peering into each room until he found a figure in the dining room. A large man was stuffing Dean's laptop into a bag, picking up medical and science equipment and shoving it in at random as well. So not someone out for his work but a more run of the mill burglar. Dean clicked the safety off the gun and raised it up as he stepped around the corner. The man half turned and froze at the sight of the gun.

"Hands up," Dean grunted, watching the guy closely in case he had his own weapon. Slowly the hands went up as the man turned to face Dean. He was older with a worn face and cold eyes. Dean felt his guard jump up, this wasn't a bumbling kid or desperate man.

"The hell you doing in my house?" It was a pointless question but Dean needed to stall. He caught the bad guy but he couldn't just call the cops with Castiel there. The man seemed to notice something was off right away as well.

"Isn't it obvious?" He drawled out, watching Dean sharply, looking for an opening. Dean didn't think for a second that the man wouldn't hurt him or even kill him if it came to it. The stairs creaked ominously and Dean jerked, just remembering to keep his eyes on the buy as he stepped back.

"Castiel go back to the bedroom!" Dean hollered out, watching the would-be robber as he yelled. The guy just smirked and raised an eyebrow; his casual attitude while standing there at gunpoint was freaking Dean out.

The stairs had gone quiet and Dean glanced over for a second.

Just a second.

The man charged him, shoving the gun away from him as he slammed Dean into a wall and wrestled for the gun. Dean kicked him off with a grunt, shoving the man backward and then cursing when he knocked over vials. Dean had the gun still but he had to dive to keep a potential explosion from happening, saving the chemical bottle before it shattered into another one or got near the portable propane tank.

It was a perfect distraction but the robber didn't run. Dean turned back to him in time to catch a punch in the face and he staggered back. The gun was yanked from his grip and Dean looked up to see Castiel in the doorway watching everything with mounting fear.

In a split second, the terror shifted into something else.

He attacked the man like an animal would. Snarling and biting at him. The guy was freaking out at the sight of the hybrid but he managed to get the gun pointed and Castiel didn't know. Dean shouted out as Castiel still charged and the man shot him point blank in the shoulder. Blood and gore splattered the walls and Castiel made a horrid sound, staggering and shocked by his first real experience with pain.

Scared eyes looked to Dean and he just reacted. Grabbing a heavy glass bottle of a harmless chemical Dean smashed it into the guy's head. He fell with a heavy thump and Dean staggered over to Castiel, yanking his shirt off to try and stagger the bleeding. A fist size chunk of his shoulder was gone, bone sticking out and blood everywhere.

"It's ok, It's gonna be ok," Dean promised mindlessly, holding the blood-soaked shirt over the gaping wound. "Fuck, it's gonna be ok Castiel."

Dean was so focused on the hybrid that he never noticed the guy getting back up. The rifle only had one bullet loaded, but the butt of the gun slammed into the back of Dean's head and everything went dark as he slumped against Castiel.

 

Waking up hurt.

Dean winced before he even opened his eyes, his head pounding painfully. He was laid out on his bed with Castiel curled up against his side. Dean jerked awake with a start when he remembered and sat up with a dizzy lurch.

There was blood everywhere.

It caked Dean's hands and bare torso. The blanket and sheets were soaked and Castiel had it all over his body. Dean scrambled to turn and inspect him, despite the pain in his head. A pillow was pressed to Castiel’s hurt shoulder and Dean gently peeled it back. Castiel gave a sleepy sound but didn't wake.

The gaping wound was closed.

The chunk was still gone, but the skin had grown over the raw wound.

Dean stared at the new flesh, gently touching the edge and getting a grumble in return. Castiel blinked tiredly at Dean before slipping off again into unconsciousness.

While Dean had aimed for Castiel to have regenerative abilities he had never thought something this fast would be possible. Twisting he checked the clock, it was ten am, less than seven hours from when the wound was inflicted.

Dean ran a hand through his hair and winced at the sharp pain. He had a lump at the back of his skull and it throbbed painfully. Dean had Codeine packed away somewhere and he stumbled from the bed to find it. Looking at the bloody mess of the bed, Dean's mind was torn between how to clean it up and trying to calculate how much blood Castiel had lost. Coming to the bottom of the stairs Dean turned into the dining room and stopped short. He surveyed the whole scene silently for a long moment before continuing to the kitchen. He made himself a coffee and took a pain killer before pulling out a kitchen chair and sitting himself down.

Sipping his coffee, Dean eyed the blood splatter from the gunshot up the wall and on the ceiling. It was Castiel's so he would collect what he could and then be careful to destroy the rest of it. There was a bullet hole in the wall as well, the worn wallpaper was torn and the wood exposed. Along the floor was a slippery mess of blood pooled, puddled everywhere and leading back upstairs. Dean was at least glad the equipment seemed to be spared; the blood was splattered away from the lab set up. His rifle was still on the floor discarded and the bag with his laptop and equipment remained where it had been dropped.

The dead robber was between them; his blank eyes gazing up at nothing.

Dean could see his neck twisted too far to the side, neatly snapped like Dean had shown Castiel.

Dean sipped his coffee and planned his day carefully.

Dragging in an old steel barrel from the back yard, Dean took it into the basement and used the garden hose to fill it with water before he dumped in a chemical mix. He let is sit while he methodically cleaned the room and floor. Bleach and household cleaner got rid of the blood, stains lingered, but Dean didn't mind those. He dragged a carpet over the worst of it. He worked his way to the stairs and up into the bedroom. Castiel was still sleeping fitfully so Dean left him. They could shower and change the bedding later. Everything would be thrown out, burned likely anyway.

For a moment Dean stared at the dead man.

But it only lasted a moment. He stripped him and dragged the body into the basement cellar. Dislocating as much as he could, Dean did equations in his head as he put the body in the barrel. A splash of the chemical mix made him jump, a few drops wouldn't hurt immediately, but it would leave a hell of a rash. Castiel staggered down the stairs, watching Dean struggle before moving in to help. His strength was clear as he lifted the body and shoved it into the barrel with ease but absolutely no care for human remains.

"Fold him up," Dean explained weakly, twisting the legs to try and get the whole body submerged. Castiel bent them with audible crunching, snapping bones like they were tissue paper. Dean felt numb to it as he directed Castiel but made sure they didn't get the mixture on them. Dean sealed the top on and stepped back, sweating as he surveyed their work. It looked like a simple metal barrel sitting in the middle of an empty cellar.

Dean thought it was odd how innocent it looked.

"Shower."

Leading Castiel upstairs Dean stripped down and got under the water, scrubbing every inch of himself and then pulling Castiel in with him to do the same. Castiel rubbed at his arms, slow and methodical in his cleaning while Dean scrubbed him over quickly but thoroughly.

"We'll go for a walk later. See if he had a truck stashed somewhere nearby. After that, we’ll use the fire pit to burn the bedding."

Castiel twisted to peer at Dean, he’d finally taken him in height and stood over Dean. A worried sound grumbled out and those big blue eyes watched Dean with anxiety.

“It’s going to be ok Cas,” Dean reassured him with a pat.

Castiel turned to face him fully and Dean scrubbed him down, working the blood off of Castiel’s chest.

With a cloth, he rubbed down along his belly and over his groin.

Castiel’s genitals were a bit of a mystery. There was a small sheath that he urinated from, a few inches long and little else. Dean had mused on it before but paid little attention beyond a medical check.

Both Bones and Ruby had been unable to breed and showed no signs of mating behavior so when Castiel reached his adolescent age and showed no hormone spikes like them Dean assumed he was the same.

But when Dean rubbed over his sheath Castiel froze for a second before jerking closer and shoving into Dean’s palm.

The tip of his sheath oozed a clear liquid and a long thin phallus slid out.

Dean jerked his hand away and Castiel just looked down at himself confused. Wide eyed he looked back at Dean, waiting to be reassured.

“You’re a real boy now,” Dean joked weakly, stepping back in to help Castiel finish cleaning.

Dean took a blood sample after the walk and fire. He found Castiel’s testosterone levels had elevated.

Clearly the intruder had caused a reaction in Castiel. Dean wondered what else in the genetic makeup of the hybrid would shift this rapidly based on various exposures. He clear adapted swiftly to his situation. Or maybe the situation had merely kickstarted what was already developing. Dean made notes on the entire thing either way.

Castiel clung to him throughout the day following him from room to room and resting his head in Dean’s lap whenever he sat down. It was an unhealthy dependency, but Dean didn’t care at that point. They were both shaken up he supposed. So Dean would stroke Castiel’s hair while he worked, putting data into files endlessly. The wound on Castiel’s shoulder had not only sealed itself but also regrew within forty-eight hours. Dean collected samples from the skin that flaked off; shedding as new stronger flesh took its place. Bone even regrew and Dean took a marrow sample. He had endless vials of blood, saliva, skin, hair, feathers, and everything else he could take with minimum pain.

Castiel had slept with Dean as soon as they arrived at the farm. He curled up and slept like a lump and Dean never really thought much about it. Now though the hybrid was going through his adolescence and as a result he was humping the bed. Dean had been woken more than once to the bed shaking. Castiel looked perplexed mostly, but he quickly figured out what felt good.

Come morning there was a slick mess on the sheet and Dean was curious. Everything about Castiel was fascinating to him and Dean knew it was messed up, but he had already gone far beyond anything remotely ok.

Dean led them up to the bedroom to create an association. He didn’t want Castiel to think reproduction was just another lab sample. Even if that was what Dean wanted.

With a set of vials on the nightstand, Dean stood Castiel by the bedside and undid his belt. Opening his pants, Dean slid them down and Castiel stepped out obediently.

Castiel made a curious noise when they didn’t go for a shower but stayed still as Dean swallowed and tried to work his nerve up. It felt too intimate, nothing like the tests but that had been Dean’s aim.

“Just gonna get a few samples,” Dean breathed, running his knuckles along Castiel’s abdomen. He was slim; build like a swimmer with compact muscle. His stomach skin was soft like a humans and Dean could see goose bumps rise under his touch. Castiel had gotten tall and Dean had to tip his head to look at his face, smiling reassuringly while Castiel watched intently.

Dean just went for it, sliding a hand down to grip Castiel’s sheath. The hybrid nearly doubled over, hands gripping Dean’s shoulders as Dean made soothing sounds. There was a sticky substance already dripping and Dean fumbled for a vial to collect some. He switched hands and got enough in the vial before setting it down. Castiel’s hips started pushing into his grip and Dean watched the phallus slowly come free. It was a good nine inches, but the girth was less than an average man. It was a paler shade then his body with a dark, blood engorged tip. Dean pushed his thumb over the head and rubbed the slit, making Castiel wobble and croon. Semen came in thick spurts and Dean was grabbing for a vial again.

Castiel came a heady amount and Dean could smell the heavy musk of it.

The hybrid stumbled back, his legs hitting the bed as he sank down to sit on the edge.

He looked up at Dean like he’d found the meaning of life and Dean chuckled. He shifted back a step and felt his own erection in his jeans.

Swallowing weakly and feeling weird again, Dean stumbled downstairs to make dinner, Castiel following.

After dinner he pushed at Dean hopefully, his hip rubbing and Dean didn’t think about it. He just reached a hand down the hybrid’s pants and jerked Castiel off. Right there in the kitchen. Castiel just thrust into his palm, quickly hurried motions with a shudder and sticky end. Dean wiped his hand on a dishcloth and Castiel sank into a chair was a satisfied sound.

“Horny bugger,” Dean mused, forcing humor even as he felt something in the pit of his stomach twist. He didn’t know how to feel about it.

They curled up for bed and Castiel rested his brow on Dean’s shoulder, spooning up against him.

Dean could admit that it felt good. He trusted Castiel and there was no need to act a certain way, to have smooth comments ready. Dean dozed off feeling strangely content.

He woke up on his back with Castiel between his thighs, thrusting miserably. Dean blinked awake, feeling the length of Castiel’s dick along his ass, sliding back and forth. His briefs were gone and Castiel was hunched over him naked, shoving and grumbling.

Had it been anyone else Dean would have decked them.

But Castiel looked so frustrated and baffled, shoving his hips but with no real knowledge of how sex worked.

He held Dean’s thighs high on his hips and had Dean propped on pillows, rocking them together without ever penetrating.

Before he could say anything, scold or coax him, Dean was suddenly struck by the realization that Castiel had him in the exact same position as Michael had when he fucked Dean on the couch. Clearly Castiel had watched them and was now trying to recreate it.

Dean didn’t know why but the thought made him react. He wrapped a hand around Castiel’s neck and the hybrid made a happy sound. Dean held him exactly like he had with Michael and whispered soft nonsense sounds as he reached between them.

His ass was slicked with Castiel’s semen already and Dean slid a finger into himself easy enough. He managed two before Castiel was whining and shoving hard at him, his cock rubbing against Dean’s hand and getting in the way. It wasn’t overly thick though so Dean leaned into the bed and pushed Castiel back. With a gruff sigh, he sat back tamely and Dean shifted them, lifting his hips so he could line them up.

Castiel’s cock slid into him slowly, pressing in as Dean sat down on it, easing inch by inch into himself. The hybrid being clueless as he was slammed himself into the pleasure and Dean hissed as the endless length went deep. Castiel’s dick was long and it felt weird buried in his ass. Castiel’s body temperature was lower then Dean’s and it made the phallus in him more readily felt.

Castiel pushed in close again, looming over Dean and rutting into him. He shoved in hard, little rabbit thrusts and surprised but happy sounds leaving his mouth as he fucked into Dean.

“G-Good boy,” Dean coaxed, groaning at the friction as Castiel just kept going.

Dean could feel the wet seep of semen, but Castiel refused to let up. Getting a hand around himself Dean only needed a few thrusts until he was coming as well.

The hybrid fucked him through it and then kept going. Dean’s ass was a wet mess as Castiel just kept fucking into him. He went long enough for Dean’s dick to come around a second time.

Dean closed his eyes and focused on the sensation of it, the slip slide inside his body. The thought that is was Castiel added to it.

Caught up in the sensations Dean jerked when Castiel took hold of his dick. He gripped too tight, but the bite of pain made Dean come with a hiss. Fumbling, Castiel tried to jerk him off, Dean reaching down to correct his hold. It felt good, but Dean wasn’t going to manage a third orgasm so close together.

But Castiel refused to let up. He gripped Dean’s hips and slammed into him, lifting Dean from the bed a bunch so he could pound in harder. Castiel looked stunned with every new sensation and he shivered, looking to Dean for comfort even as he fucked him roughly.

Dean just took it, let Castiel figure sex out at his own pace even as his ass started to ache.

Thankfully, Castiel slowed down eventually, tapering off but staying buried to the hilt and trembling.

“S’ok,” Dean slurred, worn out, as he hugged Castiel’s shoulders and rubbed his hair absently. “S’just nature Cas, you just need to follow your instincts.”

Curled up together, they were both sweat soaked and semen covered Dean fell asleep easily.

 

Come morning Dean woke reeking and sticky all over. He winced at his sore ass and burning thigh muscles as he went right for the shower. Castiel trailed and Dean couldn’t be surprised when he found himself bent over the sink, Castiel fucking into him urgently.

“You’re going to be insatiable,” he huffed with a groan. Castiel moved him as he wanted, used Dean like a rag doll not knowing better and caught up in his pleasure. It was fucked up but Dean liked it.

He liked it a lot.

With a groan he shoved into his hand and came as Castiel rode him. White lines of endless semen running down Dean’s thighs.

After a shower and good cleaning they went downstairs to make breakfast. Dean had to swat Castiel away as the hybrid kept trying to mount him. Eventually he just shoved a hand down Castiel’s pants, jerking him off with fluid motions until Castiel shuddered and came.

“And I was worried about getting samples,” Dean remarked dryly as he wiped his wet hand on a towel. “You’d probably be able to fill entire jars at the rate you're going.”

 

It was Sunday and he had planned to return to the city, but Dean hesitated now. He needed a full lab to keep working, but that meant revealing Castiel. Sam would be pissed as hell to say in the least. But even he would see just how amazing Castiel was. He was humanly structured and able to regrow missing bone, muscle, tissue, and skin in days. There was no doubt in Dean that through Castiel they would be able to grow organs and probably even limbs. It would change the medical world; rock it to the very core.

Still, Dean’s files need more work and he didn’t want to rush putting everything together. Dropping his head against the couch, Dean pulled out his phone and texted Sam, letting him know he was taking an extra day off.

Dean ignored the phone when it rang over and over.

Curling up in bed with Castiel, Dean tried not to worry about the future. Everything would work out.

Castiel nuzzled his neck and when he rolled Dean on his back he went, kicking off his briefs and welcoming Castiel. The hybrid sank into him with a satisfied sound, hips rolling lazily as he rubbed his face to Dean’s neck and shoulder. It was more languid then the night before, but Castiel still fucked Dean multiple times, coming over and over until Dean was exhausted enough that he drifted off with Castiel still gently riding him.

 

Dean woke to a car door slamming. He jerked awake, Castiel already up and looking out the window. Dean stumbled to peer out and swore at the sight of Sam storming up the driveway.

“Fuck, fuck, fuck,” Dean chanted as he fumbled to get dressed. He reeked of sex and had semen all over his thighs. Rushing he wiped at what he could and tugged jeans on over the whole mess.

“Pants,” he told Castiel who obeyed, picking his own up and getting them on, looking for his belt even though he no longer needed it to keep them on.

Yanking a shirt over his head, Dean stumbled down the stairs as Sam slammed the front door open.

“What the hell is wrong with you Dean?” He yelled, face red with anger. “I spent all week worried about you and then you say you won’t be back by a text and then won’t answer your phone. I had to use the GPS in it to track you down!”

“I know, I’m sorry. Fuck, things got messed up Sammy.”

“You think? I called Lisa, Dean.”

Wincing, Dean looked down and felt his stomach drop in guilt.

“This was all just one big fucking lie! Was it just so you could dick off and be lazy?”

“No!” Dean snapped back, glaring at his brother as guilt turned into anger, something easer to deal with. “I’ve been working my ass off alright! Doing the things no one else would.”

“And what’s that?” Sam sneered.

The floorboards upstairs creaked and from his position Dean could see Castiel at the top of the stairs.

“Don’t freak out,” Dean told Sam automatically as he motioned for Castiel to come.

“Dean, if this is one of your weird sex friends-” Sam died off, his face going slack as Castiel appeared tentatively.

Coming over to Dean, he surprised him by placing himself in front of Dean rather than hiding behind him as he usually did. But then Castiel was larger then Dean now, stronger and more agile than any human could be. He puffed himself up to look bigger and peered at Sam. He was actually a touch taller than him too.

“It’s ok big guy, Sammy won’t hurt me,” Dean reassured with a chuckle. He stepped forward to see Sam staring with clear shock.

“Amazing right?”

“Dean,” Sam croaked out weakly, looking ready to faint. “Dean what did you do?”

“Science has to move forward Sammy, no one wants to admit it, but most of our greatest accomplishments are from doing things deemed immoral at the time. Castiel is the future, Sammy. He’s a miracle,” Dean explained, hurrying over to the dining room to pull out his laptop and find the latest data.

“The things he can do, his regenerative abilities are freaking epic!” Dean grinned at Castiel and turned to Sam, watching his brother stare at Castiel unblinkingly.

“...You made a human hybrid.”

“We did, we planned him together just a few weeks ago. Hell, it feels like it was years ago.”

“We… that was a game Dean, it was just a stupid game! You actually used that?” Sam’s voice started to tremble, anger picking up again. “None of that was tested properly, we didn’t check to see what would cross over and how various aspects would react with one another. God, Dean he’s a predator not a prey animal, a carnivore. He’s dangerous.”

“So are we Sammy,” Dean growled, turning to face his brother with Castiel looking between the two worriedly. “Humans are capable of terrible things, all the worst events of history were by our hands. We chose to be what we are. Castiel’s not dangerous, he’s not like that. He's good, he chose to be.”

“He shouldn’t be able to have a choice! He should be an animal! Bones and Ruby are animals, Dean. You… you made something else completely different. Something that rivals a human.”

“Castiel doesn’t rival, he’s far better,” Dean shot back and his brother looked at him like he’d gone crazy. Sam just stared at Dean for a long breath before slowly looking around the room and taking in all the lab equipment. He ended staring at Castiel who stood a little straighter, peering at Sam curiously but weary. He was the first human aside from the robber that Castiel had met. Dean had hoped it would be a good interaction.

“Castiel…you named him after Cassie’s grandfather?”

“It’s nothing. Some stupid thing I thought up.”

“Dean... Dean did you… you used your own DNA to make him didn’t you?”

Dean blinked at the dumb question. “Where else was I going to get it?”

Sam looked horrified.

He stumbled back and leaned against the wall trembling for a moment before pushing off and walking to the door.

“Sam, wait Sam!”

When his brother ignored him Castiel moved forward. He easily slid passed them both and reached the door, closing it and blocking it in a smooth motion. Castiel peered at Sam as he stopped short and gawked at the hybrid.

“He’s dangerous Dean.”

“He isn’t, just listen to me. Listen to us,” Dean came to stand in front of his brother reaching out to hold Sam’s arms and give him a shake.

“This is a good thing, Castiel is going to change the world.”

“I…I need to go.”

“Sammy,” Dean tried, but his brother stepped away, brushing his hands off him.

“Am I allowed to go Dean?”

“What? Of course, move Cas.”

Castiel obediently stepped aside and even opened the door, watching keenly as Sam stepped around him and out. He looked freaked out by Castiel, but Dean knew with time he’d get used to him.

Sam just needed space.

“He’ll see, don’t worry.” Dean assured Castiel who slinked closer and snuggled up to Dean, resting his chin on the top of Dean’s head.

“God, you got tall huh? We’ll need to check your growth again.”

Castiel flicked his tail and looped off to the kitchen. When Dean followed Castiel was in the process of pulling out eggs and bacon from the fridge.

“Got it, food time,” Dean chuckled and looked out the window, hoping Sam wouldn’t take too long to return.

 

By nightfall, his brother did come back. He pulled up in a truck Dean recognized easily. Bobby got out of the driver’s side and Dean went to meet them on the porch.

“Hey, come in!” He grinned and was met with somber serious faces. Bobby reached back behind his seat and pulled his rifle out. Sam stepped away from the truck and Dean saw he had one as well. His stomach dropped out as he stumbled back.

“Sammy…”

“Dean. That… that thing can’t exist. If anyone finds out what you did. You’d go to jail, to a mental facility or something.” Sam sounded weak and emotional has he stepped closer.

“They’d lock him up and dissect him at worst, at best he’d still be locked up and monitored. You brought him here and all he knows is you and this place, anything else will only be torture for him.”

“Sammy, are you crazy? That won’t happen.”

“Dean... They took Ruby and Bones today. They know you messed with equipment and so they took them. Hunter Labs isn’t going to play around with this. If they figure out what you did… it would be jail at the very best.”

“So what? You’re just going to come here and fucking kill him? That’s your bright solution?” Dean snarled, standing firm on the porch and eyeing the two men. Bobby looked stone-faced and Sam apologetic.

“It shouldn’t exist, Dean,” Sam started, but Dean cut him off furiously.

“Fuck you. This is about your morals and what you want. You don’t agree with Castiel that’s fucking fine, but you don’t get to come here and decide you’re going to murder him for my sake you fucking bastard.”

“I’m not,” Sam hissed back, but Dean turned away from him.

“What about you old man? You fine with killing someone?” He snapped at Bobby who fixed him with a look.

“I don’t know what you did or why Dean, but you can’t hide away here playing house with some sort of…thing.”

Bobby could always cut right through the bullshit.

“Now I know you were hurt when that Lisa girl sent you away. It’s clear to see how bad you want a family for yourself, but this sure as shit ain’t no way to get one. Go adopted like everyone else. Not brewing up some sort of monster in your labs like a right Frankenstein freak!”

Dean glared at the man but had no sharp come back. A part of him knew there was a truth there. Lisa had said Dean was too intense, that he clung to tightly. But Dean had just wanted so badly to have a family. He wanted what his parents had. Castiel was a tiny bit of that, but he wasn’t just for Dean, he was for the world.

“So that makes it ok to kill?”

“It’s just an animal Dean,” Bobby started and Dean snorted, looking to Sam who looked off with guilt.

“Better get your facts straight,” Dean laughed coldly. “Come meet the animal.”

Dean turned and stalked back into the house.

Castiel was waiting and watching with wide but sharp eyes. Dean nodded at him but tried to get the seriousness across to him as well. It would be harder to aim the rifles in the house if things went bad.

“Jesus Fuck,” Bobby gasped out when he saw Castiel. The guns made the hybrid move to Dean’s side, straightening his back to stand tall and look menacing.

“Easy, it’s ok,” Dean muttered, not meaning it as he turned to face Castiel. When the hybrid looked at him Dean cut his eyes to the back door that was open, the screen door swaying in the light breeze. Dean pointed to it covertly with a desperate look before turning back to his brother and unofficial uncle.

“You still think he’s a god damn dog to be put down?”

Sam’s face hardened and he lifted his gun. Dean stepped forward and yanked it to point to the ceiling.

“You don’t get to pick Sammy, you're not fucking God.”

“Neither are you!” Sam growled back trying to wrestle the gun free.

“Stop it you damn idiots!” Bobby hollered as Sam shoved Dean into the table and Dean twisted to kick his brother, glass shattering.

It was the heavy smell of it that made them both freeze up. They both looked to see the broken glass bottle seeping the chemical onto the portable gas tank, eating through the metal.

“Fuck,” Sam scrambled away and Dean tried to follow but slipped. Castiel caught him and yanked him up and away right as the explosion went off. The other chemicals reacted violently to it and half the house was blown out in a matter of seconds.

Sam and Bobby where clear of the explosion, scrambling away.

Castiel whimpered above Dean, having him pinned to the floor with the hybrid over top of his body protectively.

“Cas,” Dean felt his stomach heave at the sight of him. His left arm was gone, chunks of his torso torn away as well. His wings were bloody stumps and glass shards were embedded in his back. He shivered once and puked up blood, blue eyes staring at Dean as tears formed.

“No, no, no,” Cupping his face Dean yanked his button up shirt off and tried to apply pressure to the worst of the bleeding.

“It’s gonna be ok,” he sobbed, feeling blood pouring through his fingers.

Arms grabbed him, curled around his chest and under his arms tightly before they dragged him back. Dean tried to fight, but his head was a dizzy mess.

Castiel held on to him with his remaining arm, but he was too weak, blood dripping down his chin as he watched Dean being dragged away, scrambling to follow. Sam dragged Dean clear from the house in one none stop pull. They stumbled at the driveway and Bobby helped Sam shove Dean into the truck while Dean fought them both viciously, yelling for Castiel.

“Go! The gas line is right under the dining room, go, go!” Sam shouted at Bobby and Dean yelled out as they drove down the road, the truck in reverse as Bobby slammed the gas petal down. The house shrank from sight before the next explosion lit up the night sky, the entire house collapsing almost immediately.

 

In the end, Bobby called the Hunter Labs Corporation.

They arrived in a matter of hours, a full containment unit. The firefighters and police stood aside as they explained it was a chemical fire and so needed their expertise. The whole acreage was closed up tight.

People in suits came and made threats about secret labs and Sam explained everything he knew. Dean sat numbly through it all. Feeling afloat he let the emergency crew check him out before getting on a plane Hunter Labs sent to take them to the city.

Sam sat with him in a little room with beds and a toilet for two days. All Dean could thing of was the desperate look on Castiel’s face as Dean was dragged away, his hand clutching at the floor as he dragged himself after Dean, struggling to get up and follow.

All of Dean’s data was destroyed. Everything he had done he kept on his laptop to protect it and it was completely wrecked in the explosion. The chemicals and the fire ruined all the samples and Castiel’s corpse was heavily damaged. He’d crawled under the table to avoid the fire neat the end and the acid compounds and various chemicals had doused his body when the table gave way.

Castiel had likely died in agony.

 

When Mary had married John, a nobody mechanic, she had fought with her father and they never made up. Samuel attended Mary’s funeral, shook Dean and Sam’s hand and disappeared once again. Their grandmother had died long before either Dean or Sam was born. Dean knew virtually nothing about his grandfather and couldn’t recall a time when he visited them or showed any interest in them at all.

So it came as a surprise then, when a lawyer showed up claiming to be sent by their grandfather. Sam talked to him right away, spilling the whole story. They go back and forth over the details of it while Dean slept and dreamed of Castiel clawing after him with one arm left, dripping blood and sobbing.

Dean woke with cold sweats, shaking and crying quietly.

Sam had tried to comfort him once, but Dean shoved him away, feeling too raw to be touched by anyone. He could still remember the exact feel of Castiel’s skin on his own.

 

The third day in they go down to a lab for a blood sample from Dean. The lawyer stood beside them as they took it. He prattled on about rights and laws, that Dean’s blood was only to be tested for what was agreed. Dean had no real idea what that was.

“Friendly group,” Sam remarked quietly, trying to get Dean talking. He just shrugged in reply. If he were one of them he’d want to get a look at Dean too. The man who made a ‘monster’ they were muttering.

Hunter Labs wants everything quick and quiet so they get a deal.

Sam was incredulous and then he couldn’t sign the papers fast enough. They loose all right to Ruby and Bones, they’d never work in the scientific community again after everything anyway. In return for giving them up alongside what they could recall about Castiel, they could avoid jail time.

“It’s mainly because it goes both ways. The Winchester brothers have been their stars of late, they’ve been promoting you both since your success with Ruby and Bones,” the lawyer explained.

“Right now all anyone knows is that Dean had a lab off site and was doing illegal testing. No one knows the scope or depth of what was done. The Hunter Labs Corporation want it to stay that way, they need it to stay that way. If anything gets out they’ll be ruined as thoroughly as you two.”

The lawyer, Dean can’t even recall his name, pushed papers towards Dean across the table. Sam had already signed his and was looking at Dean with a near pleading air.

“Please Dean, I just wanna go home.”

“I would highly recommend you take this deal. It won’t last very long and to be blunt it’s a hell of a lucky thing you even got it.”

Dean signed the papers.

They go home and Dean sat in the apartment, feeling lifeless. He spent his nights with horrifying nightmares of Castiel’s mutilated body.

Sam tip toes around the house at first but he eventually came looking for him. Sam could never leave anything alone for too long.

“I don’t want to do anything like this ever again,” Sam explained, sitting on the edge of the bed while Dean lied out on his stomach, facing away. “We can’t step foot in the science community now, Jess broke up with me over it. She said we’d gone off the rails and I wanted so badly to laugh at her. They had no idea Dean. Everyone thinks you just had a lab and did animal testing, that I helped you.”

Dean supposed he could feel a measure of pity for Sam. It had been entirely Dean, but Sam had been brought down with him. Through it all Sam had never once tried to change that either. Everything with the lawyer had been with them together rather then Sam leaving Dean with the full consequences of his actions.

“Bobby said you could stay with him if you need too. The house is gone and the ground needs to be cleaned properly, but the land is still worth something. Bobby said we should sell it. Hunter Labs paid us out our contracts as well in order the info on… on the hybrid. You have to go in and talk to them still. Record things and explanation of what you can remember.”

Sam sat quietly for a long moment before getting on the bed and lying down beside Dean, shoulder to shoulder. “They took your blood because of something they found on his body, a chemical compound in the skin that was weird.”

“They think he was giving something off, an addictive substance that couldn’t be felt or smelt, something microscopic. Something to attract prey but twisted around. They have theories. But it was in your blood too. They think you might have been drugged by it, addicted without ever knowing.”

Sam curled up closer with him.

“I have no idea what’s happening to you Dean, but I’m here. If you wanna talk or not. If you wanna stay with Bobby or drive to Canada, I don’t know. Or care. I just want you to get better.”

Dean turned his head and looked at his brother. His oversized idiot brother who was weeping at him with wide eyes.

Dean would always be a sucker for wide eyes.

“He was amazing Sammy.” There was no better way to explain it. Dean hadn’t been drugged or obsessed or anything. He had just genuinely loved Castiel.

“He was,” Sam agreed quietly, the lie was obvious to Dean, but it was enough for now.

Dean got up and showered. He saw Castiel in every little thing, remembering when he danced at Dean’s feet. Barely a month ago. Dean rolled his head and cracked his shoulders. It felt like years like he’d known Castiel all his life.

Hunter Labs sat him down and Dean gave his story. He left aspects out, gaps in the process and detailed they’d spend years trying to piece together. It was a petty little thing, but Dean couldn’t consider the idea of them ever trying to remake Castiel. It was a stupid thought but it burrowed deep and refused to let him go. He didn’t lie about anything, he just omitted facts.

He never mentioned what they did together. Never once hinted about the sex.

Dean went in each day for a week and spend hours upon hours talking. It became an exercise for his mind to remember all the facts that he gave and what he withheld.

A stone-faced man sat across from him, asking questions that obviously more scientifically inclined people had given him. Dean sort of delighted in fucking with him by using science terms that would confuse him or could have multiple meanings.

Dean was mildly curious though.

No one had mentioned the human remains. The fire could have burned them into nothing but if they dug up every inch of that place they had to have found something of the would-be-robber.

When they showed Dean a data compile he noticed right away. They were working off bits and pieces, tiny scraps that were tainted by the chemicals that had poured on Castiel’s body. The fire had destroyed most of it and what remained had been contaminated. Nothing had been preserved perfectly so they could only do so much.

The last day they let Dean into the lab to look. He had multiple escorts like he was going to grab the bones and run for it.

Sure enough, as Dean had theorized, it was nothing but bits and pieces, a handful of bones with potential and a whole box of them that were too damaged or tainted to be clean sources.

There was one fractured bit of skull. The ridge of the eye sockets was smooth and the eyes were set a normal distance apart, it was a human skull.

Dean signed off on the papers and left.

 

In time, they’d figure it out but Dean planned to be long gone by then. He spent his time mostly trying to figure it out for himself. Castiel had been severely hurt. Dean could only remember bits and pieces but it had seemed like the time between the first and the second explosion had been brief minutes. But then they had driven a decent length down the road. For the first time, Dean thought about the entire thing intentionally, his mind looking over the memory and picking for anything that helped build an explanation.

With a renewed vigor, he went home and started packing. Sam helped him and Dean boxed up what he couldn’t stand to get rid of and sold everything else.

His brother had huge puppy dog eyes, but he was clearly glad to see Dean shaking off his depression.

Bobby eyed him up but welcomed Dean into his home. Considering that to him Dean was essentially a mad scientist, it was a gracious and kind thing for him to do.

Dean tried to fit the role people wanted, he smiled and joked, acted like his old self. The land wasn’t properly cleaned yet but it was in the process and it was in a prime area so it sold almost immediately.

“Farmers want it, your daddy made good money off all those acres and your mishap hasn’t spoiled much of that land, barely any of it really.” Bobby explained one night, the two of them picking at dinner. Dean was more focused on the house though, the flowers in the windowsill and a lace pattern curtains, little touches with obvious meaning.

That and Ellen had come around a few times already. It made Dean happy to think of, to know the man who helped raise him after his mom died had found himself someone.

“The realtor said we got multiple offers, Sam just wants to go with the highest and be done with it.”

“You always hoped to end up there, Sam never cared,” Bobby commented and Dean shrugged.

“I can’t now. It wouldn’t be the same.”

“So now what?”

“I’ll stay here for a bit, rent someplace so I’m not cramping your style, Ellen will be relived since she’s got a kid at home,” Dean smirked as Bobby sputtered and turned red half in anger and half in genuine embarrassment.

“There’s a little place at the edge of the city I was looking at. I miss seeing the fields. After that I think I might head up north. Find somewhere quiet for a bit.”

“So long as you don’t end up like your daddy, drinking yourself to death.”

“Nah. I’ll be fine. I haven’t touched liquor since everything. I’ll work on cars or something, who knows. But that’s for later. For now I’ll hang around here until I feel ready.”

Bobby nodded his head, looking gruff but Dean could see he was pleased to hear Dean was planning, moving forward.

 

Dean sold the land and sent Sam his half. His brother visited and things seemed to slowly be getting better between them. Dean was in a small rental right on the edge of the town. It was a single room house that was worn but comfortable. Dean’s boxes were stacked up all over, unopened as he looked for a house to buy. Somewhere far off and surrounded with wilderness, Dean wanted a little cabin where he could just rest and relax.

Sam frowned over it a bit but didn’t protest, promising to help Dean move when the time came. Ellen’s daughter Jo was proving his newest distraction so Dean didn’t worry about Sam.

 

Two weeks in, Dean noticed.

He chalked it up to his mind playing tricks and stress but the thought refused to go away. Dean eventually made friends with a clinic nurse and swiped her keys for a late night ultrasound.

He laughed until he cried.

Dean wasn’t sure what would happen. If he would be able to survive it or if it would kill him. It was strange how content he felt though. For the first time in his life, he felt whole and at peace.

Maybe the whole family thing had been the key after all.

 

Nearly three months after the explosion Dean was settled and waiting in his house. On a warm summer evening he ran himself a hot bath. Dean stripped down and ran a hand over his stomach, the smallest of bumps forming already and it made Dean think of the accelerated growth he worked into Castiel’s structure.

The screen door gave a soft bang and Dean paused, one foot in the water. Sam was back in the city and Bobby was out with Ellen. No one else would come around beyond them this late in the evening.

Dean waited, anticipation building as he heard the light creek of the floorboard signaling someone coming down the hall.

He smiled, feeling the tension in him finally unraveling as Castiel filled the doorway. His arm was back and his wings regrown, he looked just like Dean remembered him with only the lightest indications of scars.

“Hello,” Dean greeted, reaching one hand out to coax him closer while the other stayed curled around his stomach.

Around their child.

“It’s going to be ok, Cas.”

**Author's Note:**

> I've been working on other stuff but I saw this prompt and I had wanted to do a Splice AU for awhile so I went for it! 
> 
> Please forgive my nonsense science, I know so little about any of it.


End file.
